1. Field of the Invention
The present invention relates to speech communication technology in the case where a telephone network is built by accommodating existent telephone sets and internet phone devices in a computer network such as a LAN (Local Area Network) and so forth.
2. Description of the Related Art
As higher operating speeds have been required of computer systems in recent years, there is a marked tendency toward increased used of an architecture wherein a LAN is built using routers or switching hubs.
Particularly on a small-scale basis, the accommodation of computer terminals in a LAN using a small-sized router is rapidly spreading. In this regard, since a higher speed and a larger capacity have also been achieved by the network being part of a trunk line, there is an increasing demand to transfer, not only computer data, but also speech signals from telephone terminals, on the LAN.
It is therefore necessary to facilitate the introduction of an internet telephone system (internet phone) into a LAN and to realize the convenient operation of the internet phone system by effectively utilizing a limited number of LAN addresses (IP addresses).
In conventional speech communications employing telephone sets, telephone exchanges are inevitably used. When the number of telephone sets to be accommodated in a telephone network increases, exchanges of larger capacity are needed to be installed in conformity with the scale of the increase.
The internet phones to be introduced into a LAN include one offered as software which is installed in and utilized by a data terminal, one offered as a dedicated telephone set which is in the same shape as that of an ordinary analog telephone set and which has a LAN interface, and one offered as the combination of a dedicated LAN connecting device and an analog telephone set housed therein.
And, in case of constructing a telephone network wherein the internet phone devices and the analog telephone sets are connected to the LAN, LAN addresses (IP addresses) are afforded to the respective devices or sets.
Further, a party to be talked to over the internet phone is designated by any of a scheme wherein the LAN address (IP address) and a domain name are used as they are, a scheme wherein a number registered and managed on the internet phone side beforehand is dialed, and so forth.
Meanwhile, apparatuses each of which accommodates a plurality of terminals therein are a repeater hub, a switching hub, a router, etc. The repeater hub electrically repeats communication signals in order to accommodate a plurality of terminals in a single network, and it does not convert or translate addresses. The switching hub is endowed with the function of accommodating a plurality of networks, in addition to the function possessed by the repeater hub, and it can also enhance security as well as a degree of load distribution among the networks, but it does not translate addresses. The router has the function of determining the sending path of each communication packet in accordance with a destination (or source) network address (IP address) affixed to the communication packet and then delivering the communication packet to the determined path, but basically it does not translate addresses. Although some recently developed remote routers include the built-in function of replacing a local address (private address) with a global address, none of them has the function of mapping a telephone number system and a network address (IP address) system each other.
Accordingly, in the case where the telephone network is built on the LAN on the basis of the prior art as stated above, there are the problems that address management becomes complicated and that the effective utilization of the LAN addresses (IP addresses) and the reutilization of the telephone sets become difficult.
The present invention has been made with the above background, and it has for its objects to minimize the number of required LAN addresses (IP addresses) and permit the formation of a system of telephone numbers being different from the LAN addresses and being unique in a telephone network, even in a case where the telephone network is built by connecting pluralities of analog telephone sets and internet phone devices to a LAN, and to realize the labor saving of an operational control job even in a case where additional telephone sets and devices constituting a LAN telephone switching system are installed, or where any of them is removed.
The first and second aspects of the present invention are premised on a LAN telephone switching apparatus (LAN telephone switching apparatus 101 in FIG. 1 of the accompanying drawings) which serves to incarnate a LAN telephone switching network on a computer network (LAN 102 in FIG. 1).
The first aspect of the present invention has the following construction:
First of all, a first network interface circuit (internet phone/data terminal accommodation module 312 in FIG. 3B) accommodates therein a network telephone set (internet phone set 313 in FIG. 3B) which has a telephone function, and which can communicate a speech signal in a state where it is stored in packets to be transferred on the computer network.
A first telephone number/network address setting circuit (address control module 320 in FIG. 3B) correspondingly sets a telephone number and a network address which are unique on the LAN telephone switching network, for the first network interface circuit.
A first packet communication circuit (address unit 307 and table unit 306 in FIG. 8B) converts the telephone number designated by the network telephone set to the corresponding network address and vice versa, and it communicates the packets containing the network address between the computer network and the first network interface circuit.
Owing to the above construction of the first aspect of the present invention, the network telephone set is permitted to join in the LAN telephone network, and speech over the network telephone set is actualized in the LAN telephone network. Herein, it is possible to form a system of telephone numbers which are different from LAN addresses and which are unique in the LAN telephone network, so the network telephone set can be used with the same feel as that of a conventional extension telephone.
Further, since the first telephone number/network address setting circuit automatically performs the address setting for the first network interface circuit, the reutilization etc. of the network telephone set are facilitated.
The above construction of the first aspect of the present invention can be so contrived that the first network interface circuit accommodates data terminal equipment besides the network telephone set, and that the first telephone number/network address setting circuit sets only one network address for the first network interface circuit. Owing to this contrivance, the illicit installation of any network telephone set can be prevented.
Also,. the above construction of the first aspect of the present invention can be so contrived that the first telephone number/network address setting circuit sets a local network address (local IP address) being unique only in the LAN telephone switching apparatus in which it is included, for the first network interface circuit, and further comprises a first network address conversion circuit (address unit 307 and table unit 306) for converting the local network address to a global network address which the LAN telephone switching apparatus possesses uniquely on the computer network, and vice versa, in the packets which are communicated by the first packet communication circuit. Owing to the contrivance, the problem of the exhaustion of the number of IP addresses can be solved.
The second aspect of the present invention has the following construction:
A second network interface circuit (analog telephone accommodation module 310 in FIG. 3B) accommodates therein an analog telephone set (analog telephone set 311 in FIG. 3B) having an analog telephone function, and it gives the analog telephone set a telephone number being unique on the LAN telephone switching network.
A signal conversion circuit (for example, A/D conversion module 309 in FIG. 3B) converts an analog speech signal to digital speech data which are communicated by the second network interface circuit, and vice versa, and it disassembles/assembles packets which contain the digital speech data and which are transferred on the computer network.
A second telephone number/network address setting circuit (address unit 307 and table unit 306) correspondingly sets the telephone number and a network address being unique on the LAN telephone switching network, for the signal conversion circuit, the telephone number being given by the second network interface circuit connected to the signal conversion circuit.
A second packet communication circuit (address unit 307) converts the telephone number designated by the analog telephone set to the network address corresponding thereto, and vice versa, and it communicates the packets containing the network address between the computer network and the signal conversion circuit.
Owing to the above construction of the second aspect of the present invention, as in the case of the construction of the first aspect of the present invention, the analog telephone set is permitted to join in the LAN telephone network, and speech over the analog telephone set is actualized in the LAN telephone network. Herein, it is provided to form a system of telephone numbers which are different from LAN addresses and which are unique in the LAN telephone network, so the analog telephone set can be used with the same feel as that of a conventional extension telephone.
Further, since the second telephone number/network address setting circuit automatically performs the address setting for the signal conversion circuit, the reutilization etc. of the analog telephone set are facilitated.
The above construction of the second aspect of the present invention can be so contrived that the second telephone number/network address setting circuit sets a local network address being unique only in the LAN telephone switching apparatus in which it is included, for the signal conversion circuit, and further comprises a second network address conversion circuit for converting the local network address to a global network address which the LAN telephone switching apparatus possesses uniquely on the computer network, and vice versa, in the packets which are communicated by the second packet communication circuit. Owing to this contrivance, the problem of the exhaustion of the number of IP addresses can be solved as in the case of the construction of the first aspect of the present invention.
The third and fourth aspects of the present invention are premised on a LAN telephone switching system which is constructed by the LAN telephone switching apparatuses as stated above.
The third aspect of the present invention has the following construction:
The LAN telephone switching system comprises a function (group table which is controlled by an address control module 320 in FIG. 3B) of giving each of the LAN telephone switching apparatuses a group of telephone numbers which are unique on the LAN telephone switching network, and a global network address which is unique on the computer network.
Also, the system comprises a function (address unit 307 and table unit 306) of communicating packets which correspond to specified network telephone sets and analog telephone sets, between the LAN telephone switching apparatuses by the use of the groups of telephone numbers and the global network addresses.
Owing to the construction of the third aspect of the present invention, it is permitted to establish communications between the specified network telephone sets and analog telephone sets which are accommodated in the different LAN telephone switching apparatuses within the computer network.
The above construction of the third aspect of the present invention can be so contrived that, when the LAN telephone switching apparatus constituting the LAN telephone switching network has been installed on the computer network anew, it is possible to report information items of the group of telephone numbers and the global network address correspondent to the installed LAN telephone switching apparatus to the other LAN telephone switching apparatuses successively. Owing to this contrivance, the dynamic addition of the LAN telephone switching apparatus is permitted and it is realized to save the labor of the operational control job of the LAN telephone switching system.
Also, the above construction of the third aspect of the present invention can be so contrived that, when a LAN telephone switching apparatus constituting the LAN telephone switching network has been removed from the computer network, it is possible to report information items of the group of telephone numbers and the global network address corresponding to the removed LAN telephone switching apparatus to the other LAN telephone switching apparatuses successively. Owing to this contrivance, the dynamic removal of a LAN telephone switching apparatus is permitted, and it is realized to save the labor of the operational control job of the LAN telephone switching system.
The fourth aspect of the present invention has the following construction:
First of all, the LAN telephone switching system comprises a function (routing table which is controlled by the address control module 320) of dividing the LAN telephone switching apparatuses constituting the LAN telephone switching system, into a plurality of groups.
Next, the system comprises a function (address unit 307 and table unit 306) of establishing communication of packets corresponding to specified network telephone sets and analog telephone sets between the groups, by accessing the LAN telephone switching apparatus which is set as a master in each of the groups.
Owing to the construction of the fourth aspect of the present invention, any of the analog telephone sets and network telephone sets which are accommodated in any of the LAN telephone switching apparatuses 101 (nodes) belonging to the LAN telephone switching system can freely communicate with any of the analog telephone sets and network telephone sets which are accommodated in the same node, or in another node within the same group, or in a different group, by the use of telephone numbers which are unique in. the system.
The above construction of the fourth aspect of the present invention can be contrived so that the master in each group is dynamically altered in accordance with a state of the communication. Owing to this contrivance, a load on searching for a telephone number on the LAN telephone switching network can be distributed over the whole network, and the reliability of a search function as the switching network can be enhanced.